<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
<style>
.active{
  border: 1px solid red;
}
</style>
</head>

<body>

     <div id="app">
        <img v-bind:src="imgSrc" alt="">
        <br>
        <img :src="imgSrc" alt="" :title="imgTitle+'!!!'" :class="isActive?'active':''" @click="toggleActive">
        <br>
        <img :src="imgSrc" alt="" :title="imgTitle+'!!!'" :class="{active:isActive}" @click="toggleActive">
    </div>
  <!-- 开发环境版本，包含了有帮助的命令行警告 -->
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
  <script>
    var app = new Vue({
      el: "#app",
      data: {
        imgSrc:"http://www.itheima.com/images/logo.png",
        imgTitle: "monkey",
        isActive: false
      },
      methods: {
        toggleActive:function () {
          this.isActive = !this.isActive;
        }
      }
    })
  </script>
</body>

</html>